DNA sequencing is a fundamental tool for biological research and medical diagnostics, driving disease gene discovery and gene function studies. DNA sequencing by synthesis (SBS) using reversible fluorescent nucleotide terminators1 is a potentially efficient approach to address the limitations of current DNA sequencing techniques, such as throughput and data accuracy. A 3′-O-allyl photocleavable (PC) fluorescent nucleotide analogue, 3′-O-allyl-dUTP-PC-Bodipy-FL-510, as a reversible terminator for SBS has previously been reported (2). The nucleotide can be efficiently incorporated by DNA polymerase into a growing DNA strand to terminate the polymerase reaction. After that the fluorophore can be photocleaved quantitatively by irradiation at 355 nm, and the allyl group is rapidly and efficiently removed by using a Pd-catalyzed reaction in water to regenerate a free 3′-OH group to reinitiate the polymerase reaction.